A note on distance-based geolocation in wireless sensor networks

Location awareness is important in many wireless sensor networks. In sensor networks because of the size, weight, battery life and price some nodes (eg, GPS-equipped nodes) are self-located but all other nodes have to determine their locations by communication with location-aware neighbors. The common method used for location determination is triangulation/lateration (referred to as 3-NA) which determines the location of a node by communication with 3 neighbors. Last year Barbeau et al proposed an improvement of 3-NA that could determine the location of a node in certain circumstances even if only two neighbors exist. The improved algorithm is called 3/2-NA by the authors. By their simulations (without theoretical analyses) they showed that for sparse sensor networks 3-NA and 3/2-NA could increase the number of location-aware nodes by up to 33% and 8% respectively. We studied the same problem and found that under the same setting our simulation results were different from Barbeau et al´s. In this paper we do theoretical analyses of 3-NA and 3/2-NA, and the analyses well match our simulation results.